Download Performance Comparison of 15 Transport

Performance Comparison of 15 Transport Ventilators
Daniel W Chipman RRT, Maria P Caramez MD, Eriko Miyoshi MD,
Joseph P Kratohvil RRT, and Robert M Kacmarek PhD RRT FAARC
BACKGROUND: Numerous mechanical ventilators are designed and marketed for use in patient
transport. The complexity of these ventilators differs considerably, but very few data exist to compare
their operational capabilities. METHODS: Using bench and animal models, we studied 15 currently
available transport ventilators with regard to their physical characteristics, gas consumption (duration
of an E-size oxygen cylinder), battery life, ease of use, need for compressed gas, ability to deliver set
ventilation parameters to a test lung under 3 test conditions, and ability to maintain ventilation and
oxygenation in normal and lung-injured sheep. RESULTS: Most of the ventilators tested were relatively
simple to operate and had clearly marked controls. Oxygen cylinder duration ranged from 30 min to
77 min. Battery life ranged from 70 min to 8 hours. All except 3 of the ventilators were capable of
providing various FIO2 values. Ten of the ventilators had high-pressure and patient-disconnect alarms.
Only 6 of the ventilators were able to deliver all settings as specifically set on the ventilator during the
bench evaluation. Only 4 of the ventilators were capable of maintaining ventilation, oxygenation, and
hemodynamics in both the normal and the lung-injured sheep. CONCLUSIONS: Only 2 of the ventilators met all the trial targets in all the bench and animal tests. With many of the ventilators, certain of
the set ventilation parameters were inaccurate (differed by > 10% from the values from a cardiopulmonary monitor). The physical characteristics and high gas consumption of some of these ventilators
may render them less desirable for patient transport. Key words: transport, mechanical ventilation, ventilator, positive end-expiratory pressure, PEEP, fraction of inspired oxygen, FIO2. [Respir Care 2007;52(6):
740 –751. © 2007 Daedalus Enterprises]
Introduction
Patients who require ventilatory support are frequently
transported from one hospital location to another. Portable
Daniel W Chipman RRT, Maria P Caramez MD, Eriko Miyoshi MD,
Joseph P Kratohvil RRT, and Robert M Kacmarek PhD RRT FAARC are
affiliated with the Department of Respiratory Care, Massachusetts General Hospital, Boston, Massachusetts. Maria P Caramez MD is also affiliated with the Department of Anesthesia, Massachusetts General Hospital, Boston, Massachusetts. Robert M Kacmarek PhD RRT FAARC is
also affiliated with Harvard Medical School, Boston, Massachusetts.
This study was partly funded by a grant from the United States Army,
DAMD 17–02-2–0006.
Daniel W Chipman RRT presented a version of this report at the OPEN
FORUM of 51st International Respiratory Congress of the American Association for Respiratory Care, held December 3–6, 2005, in San Antonio, Texas.
Conflict of interest: Robert M Kacmarek PhD RRT FAARC has received
research grants and honoraria from Respironics, Maquet Medical, Tyco
Puritan Bennett, and Hamilton Medical. Daniel W Chipman RRT is a
paid consultant for and has received lecture honoraria from Maquet Medical.
740
transport ventilators are also required in ambulances and
in forward military positions. In addition, the threat of
bioterrorism requires health care systems to be able and
rapidly with very little notice to accept and ventilate large
numbers of patients.
To provide ventilatory support under the above-defined
conditions requires that transport ventilators be appropriately designed, though this does not mean they must be
equivalent to intensive care unit ventilators.1 Transport
ventilators must incorporate certain characteristics to be of
use in the above-defined settings.1–3 First, they must be
able to ventilate patients with healthy or acutely or chronically injured lungs. Second, they must be portable and
easy to operate. Third, they must be able to deliver a high
fraction of inspired oxygen (FIO2). Fourth, in forward military positions they must be able to operate on an internal
battery for a long period, and without compressed gas.
Correspondence: Robert M Kacmarek PhD RRT FAARC, Respiratory
Care, Ellison 401, Massachusetts General Hospital, 55 Fruit Street, Boston MA 02114. E-mail: [email protected].
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
PERFORMANCE COMPARISON
Table 1.
OF
15 TRANSPORT VENTILATORS
Comparison of Evaluated Ventilators by Power Source, Physical Dimensions, Modes, FIO2, and PEEP
Approved
as
Transport
Ventilator
Ventilator
Size
Power
Requirement
Weight
Height Width Depth (kg)
(cm)
(cm) (cm)
Available Modes
FIO2
(range or
available
values)
PEEP
Available?
(range
cm H2O)
0.21–1.0
0.21–1.0
Yes, 0–20
Yes, 0–20
0.21–1.0
Yes, 0–30
0.21–1.0
Yes, 0–30
Sophisticated
Univent Eagle 754
VersaMed iVent
Yes
Yes
Electricity
Electricity
29
33
23
24
11
26
4.5
10
Newport HT50
Yes
Electricity
26
27
20
6.8
Pulmonetic Systems LTV 1000
Yes
Electricity
8
25
30
6.1
Yes
Gas
12.7
17.8
10.2
2.1
CMV, IMV
1.0
Yes
Yes
Yes
Gas
Gas
Gas
26
9.2
9.2
16
22
22
9
16.2
16.2
4.1
2.4
3.1
A/C, SIMV
CMV, SIMV
CMV, SIMV
1.0
0.5, 1.0
0.5, 1.0
Yes
Gas
15
9
0.68
CMV
Yes
No
Yes
Yes
Gas
Gas
Gas
Gas ⫹ electricity
23.5
16.76
10.6
22.9
11.1
6.35
10.6
28
16.2
8.38
16.5
12.7
4.1
0.165
0.68
4.32
Yes
Yes
Gas ⫹ electricity
Gas or electricity
25
36
30
21
12.7
21
4.5
8.5
CMV, IMV
CMV, IMV
CMV, IMV
A/C (VP), SIMV (VP),
PSV, CPAP
A/C, SIMV
CMV, IMV
Simple
Oceanic Medical Products
Magellan
Bio-Med Devices IC2A
Pneupac Parapac Medic
Pneupac Parapac Transport
200D
Life Support Products Auto
Vent 2000
Carevent ATV⫹
Vortran RespirTech Pro
Percussionaire TXP
Bio-Med Devices Crossvent 3
Bird Avian
Pneupac Compac 200
4.5
A/C, SIMV
A/C (VP), SIMV (VP),
PSV, CPAP
A/C (VP), SIMV (VP),
PSV, CPAP
A/C (VP), SIMV (VP),
PSV, CPAP
1.0
No
Yes, 0–30
No
No
No
0.6, 1.0
1.0
0.5
0.5, 1.0
Yes, 0–20
No
No
No
1.0
0.45, 1.0
No
No
FIO2 ⫽ fraction of inspired oxygen
PEEP ⫽ positive end-expiratory pressure
A/C ⫽ assist/control
SIMV ⫽ synchronized intermittent mandatory ventilation
VP ⫽ volume-controlled and pressure-controlled modes available
PSV ⫽ pressure support ventilation
CPAP ⫽ continuous positive airway pressure
CMV ⫽ controlled mechanical ventilation
IMV ⫽ intermittent mandatory ventilation
Fifth, they should be able to provide both assisted and
controlled ventilation. Sixth, they must incorporate alarms
that identify catastrophic conditions.
Previous evaluations of transport ventilators included
only up to 8 ventilators.4 –10 Many of the ventilators previously evaluated have since been modified by the manufacturers, and new ventilators have entered the market.
We present an evaluation of 15 transport ventilators for
use during intrahospital or ambulance transport and in forward military positions. The goals of this study were (1) to
determine if these transport ventilators could ventilate both
healthy and injured lungs, and deliver tidal volumes (VT)
and respiratory rates (RR) as specifically set, and (2) to
identify which ventilators would be most appropriate in
which transport settings.
Methods
Table 1 shows power requirements, physical dimen-
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
sions, available modes, available FIO2 ranges and settings,
and positive end-expiratory pressure (PEEP) range for the
15 tested ventilators. All 15 ventilators were provided by
their respective manufacturers specifically for this evaluation. All 15 ventilators are approved by the U.S. Food and
Drug Administration for use in transport, except the Vortran RespirTech Pro, which is marketed as a resuscitator.
Bench Protocol
We evaluated gas consumption, battery life, ease of use,
physical characteristics, need for compressed gas, and the
ability to deliver set ventilation parameters under 3 different test conditions. Gas consumption was defined as the
amount of time the ventilator could function on one full
E-size oxygen cylinder (capacity 660 L of oxygen), with
the ventilator set to deliver a VT of 1,000 mL at an RR of
10 breaths/min and an FIO2 of 1.0. Battery life was defined
741
PERFORMANCE COMPARISON
as the amount of time the ventilator could function on a
fully charged battery with the ventilator set to deliver a VT
of 1,000 mL at an RR of 10 breaths/min and an FIO2 of
0.21.
A ventilator was considered easy to use if all the parameters were clearly labeled and easily set to deliver a
precise variable (eg, VT or RR). We assumed the manufacturer’s published weight and dimensions to be accurate.
Ability to ventilate without compressed gas was met if the
ventilator could deliver the set minute volume (V̇E) under
each of the test conditions without a compressed gas source
or an external compressor.
The ability to deliver set parameters was evaluated with
a test lung (Training and Test Lung, Michigan Instruments, Grand Rapids, Michigan) under 3 different test
conditions: high resistance with normal compliance; normal resistance with normal compliance; and normal resistance with low compliance. High and normal resistance
was achieved with resistors (Pneuflo Rp20 and Rp5, Michigan Instruments, Grand Rapids, Michigan). Normal and
low compliance were set on the test lung (0.05 L/cm H2O
and 0.02 L/cm H2O, respectively). For each condition the
tested ventilator was set to deliver a VT of 500 mL at
15 breaths/min and 30 breaths/min, and a VT of 1 L at
10 breaths/min and 20 breaths/min.
VT, RR, peak inspiratory pressure (PIP), and positive endexpiratory pressure (PEEP) were measured and analyzed with
a cardiopulmonary monitor (NICO, Respironics, Wallingford, Connecticut) and its software (Analysis Plus, Respironics, Wallingford, Connecticut). Ventilator performance was
determined by comparing the set parameters to the measurements from the cardiopulmonary monitor.
Each ventilator was bench tested as follows. With resistance set at 20 cm H2O/L/s and compliance set at 0.05
L/cm H2O, the ventilator was connected to the test lung,
and the cardiopulmonary monitor’s flow sensor was placed
between the ventilator circuit and the flow resistor. VT was
initially set at 500 mL, RR at 15 breaths/min, inspiratory
time (TI) at 1.0 s (if setting the TI was possible on that
ventilator), and PEEP at 5 cm H2O (if PEEP was available
on the ventilator). The FIO2 was set at the lowest available
setting, which may have been 0.21, air mix (entrainment),
or 1.0, depending on the ventilator’s capabilities. Following a 10-breath stabilization period, we recorded PIP, mean
airway pressure, PEEP, VT, V̇E, RR, and the pressure,
flow, and volume graphics. After that data collection, the
RR was increased to 30 breaths/min and the TI was decreased to 0.5 s. All other settings remained unchanged.
Following another 10-breath stabilization period, we again
recorded PIP, mean airway pressure, PEEP, VT, V̇E, RR,
and graphics. The VT was then increased to 1,000 mL, RR
was decreased to 10 breaths/min, and TI was increased to
1 s. Following another stabilization period and data collection, the RR was increased to 20 breaths/min, and sta-
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15 TRANSPORT VENTILATORS
bilization and data collection were repeated. All other settings remained unchanged. These settings were repeated
for each of the compliance and resistance combinations.
The cardiopulmonary monitor was interfaced with a laptop
computer, on which the flow, volume, and pressure data
were collected and analyzed. The set ventilation parameters, ventilator-displayed values, and cardiopulmonarymonitor-measured values were simultaneously recorded.
All measurements during the bench assessment were at
atmospheric-temperature-and-pressure-dry conditions.
Laboratory Protocol
This protocol was approved by the animal care committee of Massachusetts General Hospital, Boston, Massachusetts.
Using 30-kg sheep, we evaluated each ventilator’s ability to ventilate both healthy and saline-lavage lung-injured
sheep. In both settings we evaluated the ventilator’s ability
to maintain normal arterial blood gas values and cardiopulmonary hemodynamics. We studied 12 sheep: 6 with
normal lungs and 6 with saline-lavage lung injury. Five
ventilators were evaluated on each sheep (healthy and injured), and each group of 5 ventilators was studied on 2
healthy and 2 injured sheep. Three groups of 5 ventilators
were randomly selected.
Healthy Lung Evaluation
Each group of ventilators was randomly applied for a
60-min period to a healthy sheep. Initially, each ventilator
was set at a VT of 9 mL/kg and an RR of 20 breaths/min,
with a TI or peak flow setting to maintain a TI of 1.0 s. If
the device was capable of applying PEEP, PEEP of
5 cm H2O was applied with 50% oxygen. The ventilator
was attached to the animal’s airway, followed by a 15-min
stabilization period. After stabilization we collected arterial and mixed venous blood samples, and measured systemic arterial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, and heart rate. Airway
pressure and VT were measured at the endotracheal tube
(ETT). Cardiac output was measured in triplicate, using
the thermodilution technique. The ventilator was adjusted
and oxygen added if needed to attempt to reach the target
blood gas values (PaO2 60 –100 mm Hg, PaCO2 30 –
50 mm Hg, pH 7.30 –7.50). Once we determined whether
the targets could be met, the next ventilator was attached
to the animal’s airway for evaluation.
Injured Lung Evaluation
During the lung-injury tests, the ventilator was initially
set at a VT of 6 mL/kg, an RR of 30 breaths/min, PEEP of
15 cm H2O (if available), and FIO2 of 0.50. Again, blood
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
PERFORMANCE COMPARISON
gases and hemodynamics were evaluated to determine if
the target blood gas values (PaO2 60 –100 mm Hg, PaCO2
30 –50 mm Hg, pH 7.30 –7.50) had been met, then the
ventilator was adjusted as necessary to attempt to meet the
targets. Once we determined whether the targets could be
met, the next ventilator was attached to the animal’s airway for evaluation.
Instrumentation
We used 12 female Dorset sheep (21–31 kg), each fasted
for 24 hours. Orotracheal intubation, with an 8-mm innerdiameter ETT, was performed during deep halothane anesthesia via mask. The external jugular vein was then cannulated, and an 8 French sheath introducer was inserted.
After line placement, the anesthesia delivery was changed
to intravenous only, with a loading dose of 10 mg/kg
pentobarbital, 4 mg/kg ketamine, and 0.1 mg/kg pancuronium, followed by continuous infusion of pentobarbital
(4 mg/kg/h), ketamine (8 mg/kg/h), and pancuronium
(0.1 mg/kg/h) to provide surgical anesthesia with paralysis. After intubation, the basic ventilatory settings were
volume control ventilation at a VT of 10 mL/kg, inspiratory-expiratory ratio of 1:2, FIO2 of 1.0, and PEEP of
5 cm H2O, delivered by an intensive care ventilator (840,
Puritan Bennett, Carlsbad, California). RR was adjusted to
achieve eucapnia (PaCO2 35– 45 cm H2O).
An 18-gauge catheter was then placed into the carotid
artery for continuous measurement of arterial blood pressure and sampling of arterial blood gas values. Arterial and
mixed venous blood samples were drawn for blood gas
analysis. PO2, PCO2, pH, oxyhemoglobin saturation, and
hemoglobin content were assessed with a blood gas analyzer (282, Ciba Corning Diagnostics, Norwood, Massachusetts). Flow at the ETT was measured by a heated
pneumotachometer (Hans Rudolph, Kansas City, Missouri) connected to a differential pressure transducer
(MP-45 ⫾ 2 cm H2O, Validyne, Northridge, California). Volume was determined via digital integration of
the flow signal. A differential pressure transducer
(MP-46 ⫾ 100 cm H2O, Validyne, Northridge, California) was used to measure airway opening pressure. Cardiac output and pulmonary arterial pressure were measured via a 7.5 French pulmonary artery catheter
(831 HF 7.5, Edwards Life Sciences, Irvine, California)
inserted into the left external jugular vein. Proper position of the catheter was confirmed via pressure waveform analysis before and after balloon occlusion. Following instrumentation and a 30-min stabilization period,
5 transport ventilators were randomly applied.
All signals (flow at the ETT, airway opening pressure,
arterial blood pressure, and pulmonary arterial pressure)
were amplified (8805C, Hewlett Packard, Waltham, Massachusetts), converted to digital signals with an analog-to-
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
OF
15 TRANSPORT VENTILATORS
digital converter (DI-220, Dataq Instruments, Akron, Ohio),
and recorded at a sampling rate of 100 Hz, with dataacquisition software (Windaq/200, version 1.36, Dataq
Instruments, Akron, Ohio). Ventilatory measurements
made during the animal tests were all made at body-temperature-and-pressure-saturated conditions. All infusions,
including the anesthetic, were given via volumetric infusion pump. A heating blanket was used to maintain a core
temperature of 38 –39°C. An orogastric tube was placed to
empty the stomach.
Lung Injury
Severe lung injury was produced with bilateral lung
lavage via instillations of 1 L of isotonic saline, warmed to
39°C, repeated every 30 min, until PaO2 decreased to
ⱕ 100 mm Hg at an FIO2 of 1.0 and a PEEP of 5 cm H2O.
A stable lung injury was defined as a PaO2 change of ⬍ 10%
after 60 min. It took 2– 4 lavages and 2–3 hours to establish a stable lung injury. During development and stabilization of lung injury, the animals were ventilated with the
Puritan Bennett 840 ventilator. After a stable lung injury
was established, 5 transport ventilators were randomly applied.
On completion of the protocol, the animals were sacrificed under deep anesthesia (10 mg/kg pentobarbital) with
rapid infusion of 50 mL saturated potassium chloride solution. Electrocardiogram and arterial blood pressure readings confirmed cardiac standstill.
Statistical Analysis
Formal statistical analysis was not performed. Lung
model data were compared to the ventilator settings. A
difference ⬎ 10% was considered excessive, because most
of the ventilator manufacturers indicate that the normal
range of operation is within 10% of the set parameters.
The mean ⫾ SD VT was calculated from 5 breaths.
PIP, PEEP, and RR did not change with any ventilator
during the bench evaluation. During the normal and injured-lung animal evaluations, the ability of each ventilator to achieve the target blood gas values was evaluated.
The oxygen cylinder duration and battery life were recorded in minutes.
Results
Bench Test
The 15 ventilators evaluated can be classified as either
“simple” or “sophisticated” transport ventilators, and as
those that require compressed gas (pneumatic), those that
can operate without compressed gas but require electrical
power, and those that require both or either power source.
The data in the tables and figures are organized with that
743
PERFORMANCE COMPARISON
Table 2.
OF
15 TRANSPORT VENTILATORS
Operational Features of Evaluated Ventilators: Battery, Gas Consumption, Alarms, and Ease of Use
Ventilator
Sophisticated
Univent Eagle 754
VersaMed iVent
Newport HT50
Pulmonetic Systems LTV 1000
Simple
Oceanic Medical Products Magellan
Bio-Med Devices IC2A
Pneupac Parapac Medic
Pneupac Parapac Transport 200D
Life Support Products AutoVent 2000
Carevent ATV⫹
Vortran RespirTech Pro㛳
Percussionaire TXP㛳
Bio-Med Devices Crossvent 3**
Bird Avian**
Pneupac Compac 200
Battery
Powered
Battery Life*
External Gas
Required
Oxygen
Cylinder
Duration
(min)†
Disconnect
Alarm
HighPressure
Alarm
Able to
Ventilate
Normal
Lungs
Able to
Ventilate
Injured
Lungs
Ease
of
Use‡
Yes
Yes
Yes
Yes
4h
90 min
8 h, 10 min
75 min
No
No
No
No
35
52
46
32
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
No
1
1
1
1
No
No
No
No
No
No
No
No
Yes
Yes
Yes
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4h
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
60
30
68§
62
60
65
Variable
77¶
53
30
65
Yes
No
Yes
Yes
No
Yes
No
No
No
Yes
Yes
Yes
No
Yes
Yes
No
Yes
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
No
No
No
No
Yes
No
No
No
1
2
1
1
1
1
3
3
1
1
2
*Battery life is based on tidal volume (VT) of 1 L, respiratory rate of 10 breath/min, and fraction of inspired oxygen (FIO2) of 0.21.
†The oxygen cylinder duration is the time it took to consume 1 full E-size oxygen cylinder with the ventilator set at VT of 1 L, respiratory rate of 10 breaths/min, and FIO2 of 1.0
‡Ease of use: 1 ⫽ clearly labeled and easy to access; 2 ⫽ clearly labeled but difficult to access; 3 ⫽ not clearly labeled and difficult to access.
§VT gradually decreased as cylinder became depleted to 200 mL just before the ventilator shut down.
㛳True pressure-cycled ventilator. Changes in resistance or compliance significantly altered the delivered VT. Difficult to set at desired parameters.
¶FIO2 fixed at 0.5.
**Pneumatically powered, electronically controlled ventilator. Battery and/or alternating current electricity are required for electronic controls, monitoring, etc. Compressed gas is required for
ventilation.
NA ⫽ not applicable
schema. Five of the ventilators tested can be classified as
sophisticated transport ventilators; the other ten are simple
transport ventilators.
Eight of the ventilators were purely pneumatic (they
rely completely on compressed gas and do not require any
other power source). Most of these incorporate an airentrainment device to provide different FIO2 values. The
Oceanic Medical Products Magellan and the Life Support
Products AutoVent 2000 are the exceptions; all breaths are
delivered with 100% source gas. Four ventilators were
capable of ventilating with only battery or alternatingcurrent power. Oxygen was not required, but may be added
to increase FIO2.
The third group consisted of the 3 ventilators that require both compressed gas and electricity (battery or alternating current). These ventilators incorporate a pneumatic gas-delivery system and also require battery or
alternating current to operate their electronic controls.
Table 1 shows the ventilators’ physical dimensions and
ventilation modes. There are considerable differences in
the size and weight. In some ventilators the modes are very
limited, whereas others have multiple pressure and volume
modes.
Gas consumption (Table 2) ranged from 30 min to 77 min.
744
Battery life ranged from 75 min to 8 hours and 10 min. All
except 5 ventilators (Bio-Med Devices IC2A, Bio-Med
Devices Crossvent 3, Life Support Products AutoVent
2000, Percussionaire TXP, and Vortran RespirTech Pro)
incorporated both a low-pressure/disconnect alarm and a
high-inspiratory-pressure alarm.
One interesting finding was with the Bio-Med Devices
Crossvent 3. When changing from the “Air Mix” setting to
100% oxygen, the delivered VT approximately doubled
above the set VT. According to the manufacturer, this is
expected, and the operations manual instructs to adjust the
flow accordingly.
The Percussionaire TXP was the most difficult to operate, and its controls were not clearly identified. The BioMed Devices IC2 and the Oceanic Medical Products Magellan were the only ventilators operable near a magnetic
resonance imaging device.
Tables 3 and 4 show the bench performance data. Most
of the ventilators performed at or close to specifications
under bench test conditions. The measured VT of most of
the ventilators was less than the set VT, and this discrepancy increased under conditions of increased resistance or
decreased compliance. Seventy-eight individual tests were
performed at a VT of 1,000 mL. In 32 of these tests the
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
23†
30
17†
30
15
30
16
30
15
17†
13†
25†
NA
411 ⫾ 1.3†
428 ⫾ 3.1†
487 ⫾ 0.6
483 ⫾ 1.7
507 ⫾ 1.0
306 ⫾ 0.9†
472 ⫾ 1.6
456 ⫾ 1.5
475 ⫾ 1.1
472 ⫾ 5.5
535 ⫾ 1.3
555 ⫾ 5.1†
NA
NA
30
483 ⫾ 4.2
NA
16
24
NA
12
13
20
18
14
17
31
17
26
16
20
19
31
19
25
18
21
16
PIP
(cm H2O)
NA
5
5
NA
NA
NA
7
5
6
5
7
6
5
5
7
5
5
4
4
4
9
5
PEEP
(cm H2O)
NA
560 ⫾ 3.1†
570 ⫾ 3.8†
NA
497 ⫾ 5.3
504 ⫾ 2.7
479 ⫾ 0.8
485 ⫾ 1.8
324 ⫾ 1.0†
530 ⫾ 1.2
519 ⫾ 1.8
487 ⫾ 0.8
410 ⫾ 0.9†
462 ⫾ 2.9
484 ⫾ 3.8
583 ⫾ 4.5†
570 ⫾ 5.1†
541 ⫾ 11.5
555 ⫾ 25.2†
477 ⫾ 12.1
459 ⫾ 7.4
486 ⫾ 2.0
VT
(mean ⫾
SD mL)
NA
12†
25†
NA
18†
15
30
16
30
15
30
17†
31
21†
30
15
30
15
30
15
30
15
RR
(br/min)
NA
15
16
NA
12
12
15
14
13
16
16
13
12
11
16
12
16
12
16
14
14
14
PIP
(cm H2O)
Normal Resistance and
Normal Compliance
NA
5
5
NA
NA
NA
6
5
6
6
6
6
5
5
6
5
5
5
4
4
5
5
PEEP
(cm H2O)
NA
549 ⫾ 2.0
575 ⫾ 10.7†
NA
438 ⫾ 9.8†
445 ⫾ 7.5†
461 ⫾ 11.7
462 ⫾ 10.2
312 ⫾ 2.6†
483 ⫾ 2.9
487 ⫾ 3.1
474 ⫾ 1.5
418 ⫾ 1.6†
441 ⫾ 10.4†
477 ⫾ 1.3
571 ⫾ 8.4†
555 ⫾ 3.6†
515 ⫾ 16.3
496 ⫾ 6.1
498 ⫾ 4.5
494 ⫾ 6.7
476 ⫾ 3.5
VT
(mean ⫾
SD mL)
NA
12†
25†
NA
18†
15
30
16
30
16
30
18†
32
21†
30
15
29
15
30
15
30
15
RR
(br/min)
NA
31
34
NA
24
23
27
27
20
28
32
31
27
26
29
32
34
32
32
29
30
29
PIP
(cm H2O)
Normal Resistance and
Low Compliance
NA
(Continued)
6
6
NA
NA
NA
5
4
5
5
6
6
5
4
5
5
5
4
5
5
4
5
PEEP
(cm H2O)
OF
NA
15
29
15
30
15
29
15
RR
(br/min)
554 ⫾ 3.1†
535 ⫾ 2.9
557 ⫾ 3.2†
401 ⫾ 7.1†
480 ⫾ 9.2
468 ⫾ 4.8
483 ⫾ 3.5
VT
(mean ⫾
SD mL)
High Resistance and
Normal Compliance
Bench Performance at a Tidal Volume of 500 mL
Sophisticated Transport
Ventilators
Univent Eagle 754*
Univent Eagle 754‡
VersaMed iVent*
VersaMed iVent‡
Newport HT50*
Newport HT50‡
Pulmonetic Systems
LTV 1000*
Pulmonetic Systems
LTV 1000‡
Simple Transport
Ventilators
Oceanic Medical
Products Magellan*
Oceanic Medical
Products Magellan‡
Bio-Med Devices
IC2A*
Bio-Med Devices
IC2A‡
Pneupac Parapac
Medic*
Pneupac Parapac
Medic‡
Pneupac Parapac
Transport 200D*
Pneupac Parapac
Transport 200D‡
Life Support Products
AutoVent 2000*
Life Support Products
AutoVent 2000‡
Carevent ATV⫹*
Carevent ATV⫹‡
Vortran RespirTech
Pro
Percussionaire TXP
Table 3.
PERFORMANCE COMPARISON
15 TRANSPORT VENTILATORS
745
746
6
6
4
5
29
32
23
26
15
30
14
29
475 ⫾ 1.3
488 ⫾ 2.9
390 ⫾ 8.7†
424 ⫾ 6.9†
*Respiratory rate set at 15 breaths/min
†Measured value was ⬎ 10% different from the setting on the ventilator
‡Respiratory rate set at 30 breaths/min
VT ⫽ tidal volume. RR ⫽ respiratory rate. br/min ⫽ breaths/min. PIP ⫽ peak inspiratory pressure. PEEP ⫽ positive end-expiratory pressure. NA ⫽ not applicable.
7
10
5
6
15
30
14
29
15
30
15
29
472 ⫾ 0.6
473 ⫾ 1.6
410 ⫾ 4.0†
436 ⫾ 5.0†
15
29
14
20
6
7
6
6
467 ⫾ 3.2
489 ⫾ 2.7
429 ⫾ 5.8†
442 ⫾ 5.8†
13
16
13
15
5
31
30
520 ⫾ 1.1
9
30
30
507 ⫾ 1.5
25
8
523 ⫾ 0.8
18
5
30
15
507 ⫾ 1.1
5
15
15
526 ⫾ 2.0
20
5
532 ⫾ 0.9
16
PIP
(cm H2O)
RR
(br/min)
PIP
(cm H2O)
RR
(br/min)
VT
(mean ⫾
SD mL)
PIP
(cm H2O)
RR
(br/min)
VT
(mean ⫾
SD mL)
Bio-Med Devices
Crossvent 3*
Bio-Med Devices
Crossvent 3‡
Bird Avian*
Bird Avian‡
Pneupac Compac 200*
Pneupac Compac 200‡
Table 3.
(Continued)
High Resistance and
Normal Compliance
PEEP
(cm H2O)
Normal Resistance and
Normal Compliance
PEEP
(cm H2O)
VT
(mean ⫾
SD mL)
Normal Resistance and
Low Compliance
PEEP
(cm H2O)
PERFORMANCE COMPARISON
OF
15 TRANSPORT VENTILATORS
measured VT was ⬎10% different than the set VT, and in
19 of these tests the measured RR was ⬎10% different
than the set RR.
Seventy-eight individual tests were performed at a VT
of 500 mL. In 28 of these tests the measured VT was
⬎10% different than set VT, and in 15 of these tests the
RR was ⬎10% different than the set RR. The inability to
meet the target VT is partially explained by compressible
volume loss, since none of these units compensates for the
volume loss due to compression. The compressible volume was 0.91 ⫾ 0.39 mL/cm H2O (range 0.43–1.65 mL/cm
H2O), and since the PIP values were at most in the mid30s, only about one third of the volume loss can be attributed to compressible volume. Two of the ventilators (Vortran RespirTech Pro and Percussionaire TXP) were not
included in the bench test because their design was incompatible with our protocol; they did not incorporate readily
identifiable parameter settings.
Three of the ventilators were unable to meet some of the
test conditions, due to their designs. The Carevent ATV⫹
achieves VT by setting V̇E and RR, with a maximum V̇E of
14 L/min and an inspiratory-expiratory ratio of 1:2 to establish TI. The Pneupac Compac 200 also achieves VT by
setting V̇E and RR with a maximum V̇E of 14 L/min. The
Life Support Products AutoVent 2000 has 2 controls: VT
and RR, with a maximum RR of 17–18 breaths/min. Inspiratory time and flow vary with changes in V̇E. At high
RR settings the inspiratory-expiratory ratio is ⬎1:1.
Animal Evaluations
We evaluated 14 ventilators with healthy and salinelavage-injured sheep. We were unable to evaluate the Vortran RespirTech Pro in either animal model because the
weight of the sheep (20 –31 kg) was below the operating
range of this ventilator (minimum 40 kg). All of the 14
ventilators tested were capable of ventilating the healthy
lungs (Fig. 1). Ventilators without FIO2 control met the pH
and PaCO2 targets, but exceeded the PaO2 target. With all the
ventilators, hemodynamics were stable throughout the tests.
Four ventilators (VersaMed iVent, Newport HT50, BioMed Devices IC2A, and Percussionaire TXP) met all the
targets when ventilating injured lungs (Fig. 2). Seven ventilators (Pulmonetic Systems LTV 1000, Bird Avian, Oceanic Medical Products Magellan, Pneupac Parapac Transport 200D, Pneupac Parapac Medic, Bio-Med Devices
Crossvent 3, and Carevent ATV⫹) successfully ventilated
the lungs of only one of the 2 lung-injured animals. The
remaining 3 ventilators (Univent Eagle 754, Pneupac Compac 200, and Life Support Products AutoVent 2000) failed
to meet the ventilation targets in either of the 2 lunginjured sheep used. In all cases of failure, the PaCO2 and/or
pH targets were not met. In most cases, the RR setting was
the limiting parameter. All 14 ventilators met the oxygen-
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
12†
24†
9
21
11
20
12†
21
10
17†
9
13†
NA
NA
10
20
10
20
9
18†
789 ⫾ 2.2†
870 ⫾ 3.3†
910 ⫾ 1.7
887 ⫾ 1.2†
942 ⫾ 2.9
635 ⫾ 2.0
784 ⫾ 2.7†
774 ⫾ 1.6†
925 ⫾ 1.5
913 ⫾ 4.8
1,132 ⫾ 1.9†
1,142 ⫾ 1.3†
NA
NA
975 ⫾ 0.7
972 ⫾ 0.9
950 ⫾ 2.6
947 ⫾ 2.7
917 ⫾ 1.3
654 ⫾ 6.0†
28
33
NA
NA
38
39
33
35
24
23
22
23
28
35
37
28
24
27
34
29
36
35
33
40
36
37
36
37
PIP
(cm
H2O)
5
5
NA
NA
4
5
6
8
6
6
NA
NA
6
6
7
5
5
5
6
5
5
5
5
5
4
5
5
6
PEEP
(cm
H2O)
1,164 ⫾ 1.3†
1,179 ⫾ 5.2†
NA
NA
1,016 ⫾ 1.7
1,017 ⫾ 0.8
970 ⫾ 3.1
972 ⫾ 3.1
917 ⫾ 9.8
654 ⫾ 7.3†
939 ⫾ 5.4
948 ⫾ 4.7
835 ⫾ 2.4†
952 ⫾ 2.1
937 ⫾ 1.1
973 ⫾ 3.5
653 ⫾ 2.2†
840 ⫾ 1.7†
842 ⫾ 4.2†
752 ⫾ 1.6†
1,102 ⫾ 3.1†
1,097 ⫾ 6.8
996 ⫾ 58.8
972 ⫾ 66.6
940 ⫾ 24.9
944 ⫾ 14.4
945 ⫾ 6.7
949 ⫾ 1.7
VT
(mean ⫾
SD mL)
9
13†
NA
NA
10
20
10
20
9
18†
17†
10
21
10
21
11
20
12†
25†
12†
10
20
10
20
10
20
10
20
RR
(br/
min)
25
26
NA
NA
25
25
20
21
21
15
20
20
21
20
20
24
19
21
17
16
22
22
20
20
23
24
24
24
PIP
(cm
H2O)
Normal Resistance and
Normal Compliance
5
5
NA
NA
5
4
6
7
5
5
NA
NA
5
6
6
6
6
4
5
4
5
5
5
4
3
4
5
5
PEEP
(cm
H2O)
1,125 ⫾ 5.2†
1,149 ⫾ 1.4†
NA
NA
948 ⫾ 1.1
953 ⫾ 9.7
958 ⫾ 4.7
958 ⫾ 4.0
794 ⫾ 13.6†
629 ⫾ 12.2†
896 ⫾ 4.1†
892 ⫾ 2.6†
755 ⫾ 3.2†
898 ⫾ 4.4†
886 ⫾ 4.1†
899 ⫾ 6.5†
614 ⫾ 4.6†
750 ⫾ 15.5†
850 ⫾ 7.6†
753 ⫾ 6.1†
1,055 ⫾ 4.7
1,009 ⫾ 5.7
906 ⫾ 17.3
929 ⫾ 0.8
962 ⫾ 20.2
967 ⫾ 15.4
927 ⫾ 10.8
926 ⫾ 2.1
VT
(mean ⫾
SD mL)
9
13†
NA
NA
10
20
10
20
9
18†
17†
10
22†
10
21
10
20
12†
25†
12†
10
20
10
20
10
20
10
20
RR
(br/
min)
56
58
NA
NA
51
51
52
53
42
36
44
44
42
52
52
53
36
41
47
42
56
55
51
51
52
54
52
52
PIP
(cm
H2O)
Normal Resistance and
Low Compliance
6
5
NA
NA
5
4
5
6
4
4
NA
NA
5
6
6
5
5
4
5
4
5
5
5
5
5
5
5
5
PEEP
(cm
H2O)
OF
*Respiratory rate set at 15 breaths/min
†Measured value was ⬎ 10% different from the setting on the ventilator
‡Respiratory rate set at 30 breaths/min
VT ⫽ tidal volume. RR ⫽ respiratory rate. br/min ⫽ breaths/min. PIP ⫽ peak inspiratory pressure. PEEP ⫽ positive end-expiratory pressure. NA ⫽ not applicable.
10
20
10
20
10
20
10
20
RR
(br/
min)
1,028 ⫾ 4.7
1,027 ⫾ 2.8
989 ⫾ 74.9
932 ⫾ 6.3
926 ⫾ 8.9
920 ⫾ 14.8
955 ⫾ 1.1
954 ⫾ 2.5
VT M
(mean ⫾
SD mL)
High Resistance and
Normal Compliance
Bench Performance at a Tidal Volume of 1,000 mL
Sophisticated Transport
Ventilators
Univent Eagle 754*
Univent Eagle 754‡
VersaMed iVent*
VersaMed iVent‡
Newport HT50*
Newport HT50‡
Pulmonetic Systems LTV 1000*
Pulmonetic Systems LTV 1000‡
Simple Transport Ventilators
Oceanic Medical Products
Magellan*
Oceanic Medical Products
Magellan‡
Bio-Med Devices IC2A*
Bio-Med Devices IC2A‡
Pneupac Parapac Medic*
Pneupac Parapac Medic‡
Pneupac Parapac Transport
200D*
Pneupac Parapac Transport
200D‡
Life Support Products AutoVent
2000*
Life Support Products AutoVent
2000‡
Carevent ATV⫹*
Carevent ATV⫹‡
Vortran RespirTech Pro
Percussionaire TXP
Bio-Med Devices Crossvent 3*
Bio-Med Devices Crossvent 3‡
Bird Avian*
Bird Avian‡
Pneupac Compac 200*
Pneupac Compac 200‡
Table 4.
PERFORMANCE COMPARISON
15 TRANSPORT VENTILATORS
747
PERFORMANCE COMPARISON
OF
15 TRANSPORT VENTILATORS
Fig. 1. PaCO2, arterial pH, and ratio of PaO2 to fraction of inspired oxygen (FIO2) in healthy (no lung injury) sheep during ventilation with 14
transport ventilator models. Each set of values represents data from a single sheep. Assessment was performed on 2 sheep with each
ventilator. The large variability in the ratio of PaO2 to fraction of inspired oxygen (PaO2/FIO2) is because some of the ventilators only offer only
1 or 2 FIO2 settings, and because of the level of gas exchange in each sheep. The Vortran RespirTech Pro could not be used on the animals
we tested. The Percussionaire TXP and the Vortran RespirTech Pro could not be set to the specifications required by the lung model.
U ⫽ Univent Eagle 754. P ⫽ Pulmonetic Systems LTV 1000. V ⫽ VersaMed iVent. B ⫽ Bird Avian. M ⫽ Oceanic Medical Products Magellan.
N ⫽ Newport HT50. PT ⫽ Pneupac Parapac Transport 200D. PM ⫽ Pneupac Parapac Medic. C ⫽ Pneupac Compac 200. BI ⫽ Bio-Med
Devices IC2A. BC ⫽ Bio-Med Devices Crossvent 3. CV ⫽ Carevent ATV⫹. A ⫽ Life Support Products AutoVent 2000. PC ⫽ Percussionaire
TXP.
ation target under all conditions with the lung-injured sheep.
As with the uninjured sheep, with all the ventilators the
hemodynamics were stable throughout the tests.
Discussion
The major findings of this study are:
1. All the evaluated ventilators were able to maintain
normal ventilation and hemodynamics in healthy sheep.
2. In the lung-injured sheep, few of the ventilators could
be set to meet the PaCO2 or pH targets. The ventilators
unable to meet these targets were limited by the RR setting.
3. In the bench study, only 6 of the ventilators met the
VT and RR settings under all the test conditions.
4. Only 5 of the ventilators (Univent Eagle 754, VersaMed iVent, Newport HT50, Pulmonetic Systems LTV
1000, and Pneupac Compac 200) can operate without a
compressed gas source, and their battery life differed considerably.
5. A full E-size cylinder of oxygen allowed ventilation
with 100% oxygen for only 30 –77 min.
6. The 2 ventilators most suitable for use in front-line
rescue situations, where oxygen may not be available, are
the Newport HT50 and the Univent Eagle 754.
748
Use of Transport Ventilators
Transport ventilators are required in various settings:
intra-hospital, inter-hospital, pre-hospital, and in the field
by military or civilian authorities.3 Each of these settings
has different priorities regarding ventilator design. In forward military or field use by civilian groups, the ideal
ventilator would be simple to operate, battery powered,
compact, lightweight, and would operate without compressed gas. In that setting it is unlikely that the patient
will be breathing spontaneously, so versatility of available
modes is unnecessary. Similar issues exist during pre-hospital transport, but compressed gas is readily available in
most ambulances, so a pneumatically operated ventilator is
as acceptable as a battery operated unit. During inter-hospital transport the patient may be breathing spontaneously,
which necessitates patient-triggered ventilation, and frequently these patients require high FIO2.
The most common use of transport ventilators is in intra-hospital transport. At Massachusetts General Hospital,
the respiratory care department performs about 30 oneway patient transports per day and another 10 –15 are performed by the anesthesia department, all of which require
continuous mechanical ventilation. Most of these trans-
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
PERFORMANCE COMPARISON
OF
15 TRANSPORT VENTILATORS
Fig. 2. PaCO2, arterial pH, and ratio of PaO2 to fraction of inspired oxygen (FIO2) in lung-injured sheep during ventilation with 14 transport
ventilator models. Each set of values represents data from a single sheep. Assessment was performed on 2 sheep with each ventilator. The
large variability in the ratio of PaO2 to fraction of inspired oxygen (PaO2/FIO2) is because some of the ventilators only offer 1 or 2 FIO2 settings,
and because of the level of gas exchange in each sheep. The Vortran RespirTech Pro could not be used on the animals we tested. The
Percussionaire TXP and the Vortran RespirTech Pro could not be set to the specifications required by the lung model. U ⫽ Univent Eagle
754. P ⫽ Pulmonetic Systems LTV 1000. V ⫽ VersaMed iVent. B ⫽ Bird Avian. M ⫽ Oceanic Medical Products Magellan. N ⫽ Newport
HT50. PT ⫽ Pneupac Parapac Transport 200D. PM ⫽ Pneupac Parapac Medic. C ⫽ Pneupac Compac 200. BI ⫽ Bio-Med Devices IC2A.
BC ⫽ Bio-Med Devices Crossvent 3. CV ⫽ Carevent ATV⫹. A ⫽ Life Support Products AutoVent 2000. PC ⫽ Percussionaire TXP.
ports are to and from diagnostic areas, the operating room,
or the emergency department.
It is well documented that transport ventilators provide
more stable gas exchange and hemodynamics than manual
ventilators.10 –13 Gervais et al11 observed severe respiratory
alkalosis during transport with manual ventilation. In 20 patients transported to diagnostic areas, Braman et al12 found
substantial respiratory acidosis or alkalosis and hemodynamic
compromise in 16 patients receiving manual ventilation. Hurst
et al13 also documented respiratory alkalosis during intrahospital transport of 28 patients receiving manual ventilation.
Nakamura et al10 also observed greater variability of gas
exchange and hemodynamics during transport with manual
ventilation than with a transport ventilator.
Types of Transport Ventilators
Austin et al3 classified transport ventilators into 3 categories, based on their capabilities: automatic resuscita-
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
tors, simple transport ventilators, and sophisticated transport ventilators. They defined a simple transport ventilator
as one that provides a specified rate and volume with a
high-pressure relief valve,3 whereas a sophisticated transport ventilator has modes that allow spontaneous breathing, and additional alarms and monitors of gas delivery.
Five of the ventilators we evaluated were sophisticated:
Newport HT50, Univent Eagle 754, VersaMed iVent, Pulmonetic Systems LTV 1000, Bird Avian.
We considered the Newport HT50 and the Univent
Eagle 754 most suited for use in forward military positions, because they have longer battery life (8 hours
and 4 hours, respectively). The VersaMed iVent was the
heaviest of the units evaluated (10 kg). However, the
Newport HT50, Univent Eagle 754, VersaMed iVent,
and Pulmonetic Systems LTV 1000 clearly could function exceptionally well in all transport settings if they
had longer battery life. The Bird Avian was the most
749
PERFORMANCE COMPARISON
limited in this regard, because it lacks a battery and
needs compressed gas to operate.
Issues/Problems With Specific Ventilators
The choice of a ventilator is also determined by other
specific design issues. Only 2 of the ventilators (Bio-Med
Devices IC2 and Oceanic Medical Products Magellan) are
designed for use during magnetic resonance imaging. The
following ventilators had no alarms: Vortran RespirTech
Pro, Bio-Med Devices IC2, Percussionaire TXP, Oceanic
Medical Products Magellan, and Life Support Products
AutoVent 2000.
Many of the ventilators allow very few FIO2 values: Vortran RespirTech Pro (FIO2 1.0), Bio-Med Devices IC2 (FIO2
1.0), Oceanic Medical Products Magellan 2000 (FIO2 1.0),
Pneupac Parapac Transport 200D (FIO2 0.5 or 1.0), Pneupac
Parapac Medic (FIO2 0.5 or 1.0), Bio-Med Devices Crossvent 3 (FIO2 0.5 or 1.0), Carevent ATV⫹ (FIO2 0.8 or 1.0),
and Life Support Products AutoVent 2000 (FIO2 1.0).
The oxygen cylinder life of the Pneupac Parapac Medic
exceeded the maximum estimated time (66 min), because
VT gradually decreased as the cylinder became depleted to
200 mL just before the ventilator shut down.
With the Percussionaire TXP, the maximum FIO2 delivered was 0.5, which accounts for its 77-min cylinder life.
Note, however, that the volume of gas in E-size cylinders
does vary, because filling pressure varies, which adds to
the variability in cylinder life.
With the Newport HT50 and its nondisposable proprietary circuit, intrinsic PEEP developed at higher RR because of high expiratory resistance. With the Bio-Med
Devices IC2, Life Support Products Magellan 2000, Pneupac Parapac Transport 200D, and Pneupac Parapac Medic
the VT is set with the flow rate and TI controls, and RR is
controlled by those two plus an expiratory time control.
With the Carevent ATV⫹, VT is determined by V̇E and
RR. The Life Support Products AutoVent 2000 has 2 controls (RR and VT), its maximum RR is 18 breaths/min, and
it does not have any alarms. The Pneupac Compac 200 is
designed for military use. It has a sturdy case, and VT is
adjusted by setting V̇E and RR. It has a fixed TI of 1 s and
a maximum RR of 26 breaths/min. The Percussionaire
TXP is a pressure-limited and time-cycled ventilator, and
its VT varied with changes in impedance, but we found
that even with constant impedance the VT drifted upwards.
The maximum RR with the Life Support Products
AutoVent 2000 is 18 breaths/min, and with the Carevent
ATV⫹ it is 40 breaths/min. With the Oceanic Medical
Products Magellan, setting RR at 15 breaths/min and
20 breaths/min resulted in measured RR of 23 breaths/min
and 30 breaths/min, respectively.
The most difficult ventilator to evaluate was the Vortran
RespirTech Pro. This ventilator has few clearly labeled
750
OF
15 TRANSPORT VENTILATORS
controls, and the manufacturer’s specified patient-weight
range was outside the weight range of the animals we
used. However, it is the smallest and lightest of the ventilators we tested, and it is only for single-patient use.
It may be necessary with some of these ventilators to
monitor gas delivery with a secondary monitor because of
the large difference between the set and actual VT and RR.
Since we did not assess these ventilators during spontaneous breathing, we cannot comment on patient-ventilator
synchrony or the difference between the set and delivered
parameters during spontaneous ventilation.
Comparison With Other Studies
Nolan et al5 evaluated the performance of 6 pneumatically operated ventilators. Similar to our results, they noted
that the overall ability of the ventilators they tested to
maintain delivered VT, V̇E, and RR consistent with the set
levels diminished as resistance increased or compliance
decreased. McGough et al6 observed the same problem
with 8 pneumatically operated ventilators they evaluated
with a test lung. The Univent 750 was evaluated by Campbell et al,7 with a test lung, during controlled and patienttriggered ventilation. They observed, as we did, that with
the Univent Eagle 754, gas delivery was not markedly
affected by a decrease in compliance or an increase in
resistance.
More recently, Miyoshi et al8 evaluated 4 ventilators
with transport capabilities, all with internal batteries. However, at least 3 of these units (Puritan Bennett 740, Bird
T-Bird, and Respironics Espirit) would not be considered
typical transport ventilators. However, all of these units,
along with the Pulmonetic Systems LTV 1000, were capable of ventilating a test lung during assisted ventilation,
at various ventilation settings.
Zanetta et al9 evaluated 5 transport ventilators and 3
intensive care unit ventilators during controlled and patient-triggered ventilation with a test lung. They determined that VT varied ⬍ 10% as delivered VT varied from
300 mL to 800 mL and compliance and resistance were
varied. However, they noted that, because of high resistance to exhalation, all the portable ventilators they evaluated trapped gas at high V̇E.
Limitations
The primary limitation of the present study is that it was
not performed with patients. However, the bench and animal evaluations did simulate common settings required
by patients during controlled ventilation. In addition, the
animal model evaluations were consistent with pediatric
patients, not adults. This limited the assessment of some of
the ventilators. We also did not evaluate any of these
ventilators during spontaneous breathing, which is clearly
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
PERFORMANCE COMPARISON
a major issue in transport within and between hospitals. As
a result, we cannot comment on their performance during
spontaneous triggering. Also, we evaluated only one ventilator from each company, and we cannot be sure that the
single ventilator we tested reflects the operation of all
ventilators of that model.
Conclusions
Only 2 of the transport ventilators evaluated met the trial
targets in all bench and animal settings. With some ventilators the settings were inaccurate. The physical characteristics
and high gas consumption of some of these ventilators may
render them less desirable for patient transport.
REFERENCES
1. Branson RD, McGough EK. Transport ventilators. Probl Crit Care
1990;4:254–274.
2. Branson RD. Intrahospital transport of critically ill, mechanically ventilated patients. Respir Care 1992;37(7):775–793; discussion 793–795.
3. Austin PN, Campbell RS, Johannigman JA, Branson RD. Transport
ventilators. Respir Care Clin N Am 2002;8(1):119–150.
4. Johannigman JA, Branson RD, Campbell R, Hurst JM. Laboratory
and clinical evaluation of the MAX Transport Ventilator. Respir
Care 1990;35(10):952–959.
RESPIRATORY CARE • JUNE 2007 VOL 52 NO 6
OF
15 TRANSPORT VENTILATORS
5. Nolan JP, Baskett PJF. Gas-powered and portable ventilators: an
evaluation of six models. Prehospital Disaster Med 1992;7(1):25–
34.
6. McGough EK, Banner MJ, Melker RJ. Variations in tidal volume
with portable transport ventilators. Respir Care 1992;37(3):233–
239.
7. Campbell RS, Davis K Jr, Johnson DJ, Porembka D, Hurst JM.
Laboratory and clinical evaluation of the Impact Uni-Vent 750 portable ventilator. Respir Care 1992;37(1):29–36.
8. Miyoshi E, Fujino Y, Mashimo T, Nishimura M. Performance of
transport ventilator with patient-triggered ventilation. Chest 2000;
118(4):1109–1115.
9. Zanetta G, Robert D, Guerin C. Evaluation of ventilators used during
transport of ICU patients: a bench study. Intensive Care Med 2002;
28(4):443–451.
10. Nakamura T, Fujino Y, Uchiyama A, Mashimo T, Nishimura M.
Intrahospital transport of critically ill patients using ventilator with
patient-triggering function. Chest 2003;123(1):159–164.
11. Gervais HW, Eberle B, Konietzke D, Hennes HJ, Dick W. Comparison of blood gases of ventilated patients during transport. Crit Care
Med 1987;15(8):761–763.
12. Braman SS, Dunn SM, Amico CA, Millman RP. Complications of
intrahospital transport in critically ill patients. Ann Intern Med 1987;
107(4):469–473.
13. Hurst JM, Davis K Jr, Branson RD, Johannigman JA. Comparison of
blood gases during transport using two methods of ventilatory support. J Trauma 1989;29(12):1637–1640.
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